Automatic reclosing circuit breakers



5 In Second Oct. 30, 1956 J. M. WALLACE ET AL 2,769,055

AUTOMATIC RECLQSING CIRCUIT BREAKERS Filed May 15 1951 T ReclosingReclosing Reclosing 92 Breaker 93 Breaker 35% 93 Breaker Fig.2. A B 97 CTime 50 IOO 600 Curreni in Amperes WITNESSES:

INVENTORS James M.Wc|loce 0nd YAlfred R.MCCIung.

AUTOMATIC RECLOSING CIRCUIT BREAKERS James M. Wallace, Pittsburgh, Pa.,and Alfred R. Mc-

Clung, Smithers, W. Va., assignors to Westinghouse Electric Corporation,East Pittsburgh, Pa., a corporation of Pennsylvania Application May 15,1951, Serial No. 226,494

11 Claims. (Cl. 200-89) Our invention relates, generally, to circuitinterrupters, and it has reference in particular to circuit interruptersof the automatic rec-losing type which may be connected forsectionalizing a distribution line.

In applying automatic reclosing circuit breakers to distribution lines,it is generally customary to have them operate with one or moreinstantaneous operations and to arrange them in descending order ofratings, as they are located more distant from the source, so that eachwill coordinate with the preceding one. Practical limitatrons are placedon the number of difierent ratings by the margin between ratingsnecessary to avoid possible overlap, because of variations due tomanufacturing tolerances.

If a high degree of sectionalizing of a line is desired, thelength ofline which may be protected with reclosing breakers of standard ratingswill necessarily be short. A device which could be applied betweenreelosing breakers of the usual ratings would double the possible numberof such sectionalizing points on a line.

Accordingly, it is an object of our invention to provide an automaticreclosing circuit breaker whose operating characteristics vary withOperating conditions of the circuit.

Another object of our invention is to provide an automatic reclosingcircuit breaker which operates in response to currents in excess of apredetermined value under one operating condition, and operates inresponse to a much lower value of current under another condition.

Yet another object of our invention is to provide in an automaticreclosing circuit breaker for so controlling the operation thereof as toeffect delayed operation in response to predetermined current conditionswhen the line voltage is above a certain value, and instantaneousoperation in response to predetermined current conditions when the linevoltage drops below a normal value.

We further propose as an object of our invention to provide in anautomatic reclosing circuit breaker 'for utilizing electromagnetic meansresponsive to the voltage of the circuit at the breaker for maintaininga time delay device in a maximum delay position if the voltage remainsat a normal value.

Another important object of our invention is to provide in an automaticreclosing circuit breaker of the type having dashpot delay means withcounting means operable to vent the dashpot, for biasing the countingmeans to the venting position and utilizing electromagnetic restrainingmeans for opposing the action of the biasing means, so as to maintainthe timing means in the delayed operation position so long as thevoltage of the circuit does not fall below a critical value.

A further object of our invention is to provide in a distribution systemfor using a recloser which normally has greater time delay than asucceeding breaker of the same rating, but which knows when a breakerahead of it operates, and thereupon changes its characteristics toprovide for instantaneous operations.

These and other objects of this invention will become United StatesPatent 2,769,055 Patented Oct. 30, 1956 'ice apparent upon considerationof the following detailed description of preferred embodiments thereof,when taken in connection with the attached drawing, in which:

Figure l is a longitudinal section view through a circuit breakerembodying this invention;

Fig. 2 is a schematic showing of a distribution circuit with a typicalarrangement of automatic reclosing circuit breakers iliustrating anapplication of the breaker of Fig. 1;

Fig. 3 is a chart showing typical time-current curves for the circuitbreakers of Fig. 2.

The circuit breaker illustrated in Fig. l is contained in a metal tank 2having an open top adapted to be covered by a hollow cover structure -4which may be secured to tank -2 in any desired manner. Preferably, themajor part of the interior of tank 2 is covered by a suitable insulatingliner 3, of any desired insulating material, such as fiber or the like.The tank 2 may be filled with a suitable insulating liquid such as oilor the like, as designated by the liquid level line L. The circuitbreaker operating mechanism is all adapted to be mounted on the cover 4,which may have supports 6 (only one of which is shown), at least partlyof insulating material for supporting a supporting casting S and asupporting plate 10 between which a solenoid coil 12 may be mounted:Stationary contacts 14 for the breaker may in turn be suspended fromsupporting plate 10 by means of a tube 16 of insulating mate rial, suchas fiber or the like.

A bridging contact bar 18 is adapted to bridge stationary contacts 14,and is mounted on the lower end of a Contact rod 22, as by a pivot 20,about which the bridging contact may have limited pivotal movement. Theupper end of contact rod 22 is connected by a pair of pivoted connectinglinks 24 of insulating material, such as fiber or the like, to thecommon pivot 26 of a pair of toggle levers 28 and 30. Toggle lever 28 isadapted to be held in engagement with a pivot bracket 32 supported fromcover 4, by a coil tension spring 34 secured at one end to cover 4, andat the other end engaging an opening in toggle lever 30.

Spring 34 acts, at the position of the parts shown in Fig. 1, to biasbridging contact 18 into engagement with stationary contacts 14 of thebreaker with a predetermined pressure. However, if contact rod 22 ismoved upwardly, the pivot point 26 of toggle levers 28 and 30 movesupwardly with the contact rod and this movement is opposed by contactpressure spring 34. However, the line of action of contact pressurespring 34 approaches the oncenter position of toggle levers 23 and 30during the first part of contact opening movement, so that theopposition of this spring to such opening movement rapidly decreases tosubstantially Zero when the toggle levers are at their on-centerposition. The contact separating movement re quired to move togglelevers 28 and 30 from their positions shown in Fig. 1 to their on-centerposition is kept small because separation of these levers is limited bya hook portion 29 on toggle lever 30 which extends through an opening intoggle lever 28 to limit separation of the levers to a relatively smallamount. Furthenmore, during the first part of contact separatingmovement, the levers 28 and 30 are moved to their on-center position asdescribed above, and at this position, lever 30 engages lever 28 so thatfurther relative movement in the same direction is prevented, andaccordingly, contact pressure spring 34 ofiers substantially noopposition to further contact separation.

After a circuit opening operation by contact rod 22, the force ofgravity acts on bridging contact 18 and contact rod 22 to cause theseparts to move downwardly toward stationary contacts 14. As is the caseduring the latter part of contact separating movement, contact pressurespring 34 will have substantially no effect on the circuit closingoperation, until the line of action of contact pressure spring 34 movesbelow the pivot point of toggle lever 28 on bracket 32, whereupon thisspring becomes effective suddenly to rapidly move the bridging contact18 into engagement with stationary contacts 14 and to exert theaforementioned contact pressure thereon.

In order to manually operate the circuit breaker contacts, and also toprovide for a locked-open condition of the breaker, there is provided apair of toggle levers 36 and 38 connected by a knee pivot pin 4ft, withlever 36 being pivotally mounted in cover 4, as by a pivot pin 42, andbeing extended beyond this pivot pin to the exterior of cover 4 where itnormally is positioned beneath a hood portion 46 integral with thecover. A handle extension 44 of lever 36 has an operating eye 48 at theouter end thereof for receiving a hook stick or similar operatingmember. The other toggle lever 38 is provided with a slot 50 at itsouter end for receving a pin 52 mounted between spaced supporting lugs54 integral with cover 4. A coil compression lock-out spring 56 ismounted on toggle lever 38 so as to react between supporting lugs 54 anda shoulder provided at the inner end of toggle lever 38. Preferably,toggle lever 38 has an inwardly and downwardly extending operatingextension 58 adapted to be engaged by automatic counting means, as willbe described.

It will be observed that toggle levers 36 and 38 are shown in Fig. l ofthe drawing as being held at a position slightly below center by spring56, with knee pivot 49 below a line drawn between pivot 42 of lever 36and supporting pin 52 for lever 38, and that a stop bolt 49 mounted inhood 46 of the cover defines this over-center position of the togglelevers. When it is desired to manually open the breaker contacts, handle44 may be pulled downwardly to move the knee pivot 40 of toggle levers36 and 38 upwardly over center, whereupon spring 56 assists in furtherupward movement of toggle knee pivot 40. Inasmuch as the toggle kneepivot pin 40 is extended to lie beneath a flange on toggle lever 28,upward movement of this pivot pin likewise causes upward movement oftoggle lever 23, contact rod 22, and bridging contact 13 to an opencircuit position. Following such a manual circuit opening operation,handle 44 may be manually moved upwardly back to the position shown inFig. l Where toggle levers 36 and 38 will be maintained by spring 56, tothereby permit reclosing of the breaker contacts in the same mannerdescribed above. With toggle levers 36 and 38 in the position thereofshown in Fig. 1, it is obvious that operating extension 58 of lever 38,if moved upwardly, will have the same effect as downward movement ofhandle 44, that is, to cause opening of the breaker contacts, to alocked-open position at which they are held by spring 56.

For the purpose of automatically separating bridging contact 18 fromstationary contacts 14 of the breaker in response to overloads, there isprovided an actuating sleeve 66 which receives an intermediate portionof contact rod 22, with the lower end of this sleeve being threaded intoa solenoid core 62 having a central opening for receiving contact rod22, and being slidably mounted in'a central opening provided in coilsupporting plate 10. A light coil compression spring 64 reacts between apin 66 on contact rod 22 and solenoid core 62 to normally bias thelatter to the position shown in Fig. l. Preferably, solenoid coil 12 isprovided with suitable insulation covering the coil, and the interior ofthe coil additionally has a cylindrical dashpot sleeve 70 of insula ingmaterial, such as fiber or a molded insulating material receivedtherein. For the purpose of limiting upward movement of actuating sleeve60 on contact rod 22, the latter is provided with a flange 72 adjacentthe upper end thereof. The upper end of dashpot sleeve 75) is providedwith an annular outlet passage 74 formed in supporting casting 8, andcommunicating with a laterally extending vent passage 76 also formed inthe supporting casting which opens to the interior of casing 2. Theouter end of the passage 76 may be threaded for receiving a plug whendelayed operation is desired on all breaker openings.

It will now be apparent that upon the passage of currents throughsolenoid coil 12 of a value sufliciently high to attract core 62, thatthe latter will be moved upwardly while stressing spring 64. Dependingupon whether or not vent passage 76 is open, or closed by a plug orother means to be hereinafter described, upward movement of core 62 andactuating sleeve 66 will be relatively fast (if vent passage 76 is open)or relatively slow (if vent passage 76 is closed), due to the necessityof liquid trapped within the dashpot sleeve 70 escaping through therelatively small clearances between core 62 and the opening insupporting plate 16 when the vent passage is closed. In either case,however, spring 64 eventually becomes compressed to an extent thatcontact pressure spring 34 is overcome and contact rod 22 then begins tomove upwardly to separate bridging contact 18 from stationary contacts14 in the manner previously described. In the event of any difficultywith spring 64-, upward movement of core 62 and actuating sleeve 66 willeventually cause the latter to engage the flange 72 on contact rod 22 topositively separate bridging contact 18 from stationary contacts 14.When solenoid coil 12 becomes deenergized, the contacts may close in themanner previously described, except that the speed of reclosing movementwill be dependent, as is the speed of contact opening movement, uponwhether or not vent passage 76 is open or closed.

For the purpose of counting closely succeeding circuit interruptingoperations of the circuit breaker, there is provided a cylindricalsleeve 78 mounted in an opening provided in supporting casting 8intersecting vent passage 76, and a counting piston St is adapted to bemounted in sleeve 78. The lower end of sleeve 73 is closed by a plughaving a small opening for restricting the flow of fluid and beingcontrolled by a ball check valve 82, so that while fluid may be drawninto the lower end of sleeve 78, it cannot escape outwardly from thelower end of the sleeve. Counting piston 80 has a reduced upwardlyextending rod portion provided with a plurality of spaced flanges 84thereon, and above this it has secured thereto an extension 86, for apurpose to be described.

A pawl lever 92 is pivoted at one end. as at 94 on supporting casting 8,and has its other end engaging the top of a collar 96 secured toactuating sleeve 66 so that the lever will be moved upwardly each timethe breaker contacts separate. Pawl lever 92 has a pawl member 98mounted thereon which is adapted to engage beneath a flange 34 of thecounting piston to move the piston upwardly each time the breakercontacts separate.

It is believed clear that upon the occurrence of a circuit openingoperation, counting piston 80 will be moved upwardly a predetermineddistance by pawl member 98, and when the breaker contacts are reclosed,counting piston 80 will remain at the position to which it was advancedon the preceding circuit opening operation. Counting piston 80 willreturn very slowly to its normal lowermost position illustrated in Fig.1 under the force of gravity, it being retarded in such return movementby the necessity of displacing liquid drawn into the lower end of sleeve78 when the piston was advanced, through the relatively small clearancespace between the piston and sleeve 78. However if a number of circuitopening operations occur in close succession, counting piston 80 willnot have time to return to its normal lowermost position shown in Fig.1, because when the contacts, reclose, they will immediately reopen, andthis time pawl member 98 will engage the next lowermost flange 84 of thecounting piston to advance the latter a further amount upwardly, andthis will continue until the extension 86 of the Qounting piston engagesoperating extension 58 of toggle level 38 to move the knee pivot 40 oftoggle levers 36 and 38 upwardly over center, whereupon the breakercontacts will be locked. out in the manner previously described.

Another function of counting piston 80 is to control vent passage 76leading from the upper end of dashpot sleeve 70. In a normal breaker,the small cross-section area extension of counting piston 80 ispositioned in the region of the transverse openings through cylindricalsleeve 78 in alignment with vent passage 76, so that relatively freeventing of fluid from the upper end of dashpot sleeve 70 is possible,and accordingly, upward movement of solenoid core 62 is relativelyunimpeded so that the first circuit opening operation will occursubstantially instantaneously .after the current through coil 12 reachesa value sufiicient to attract core 62. Assuming that the contacts thenreclose and are again immediately reopened due to excess current stillbeing present in the circuit, counting piston 80 itself may be advancedto a position blocking vent passage 76, or this may not occur until thethird closely succeeding circuit interrupting operation, depending uponthe length of sleeve 78 in which the piston is located, and on thelength of the piston and its reduced upward extension. In either case,piston 80 will eventually be advanced to a position where it does blockvent passage 76 so that the next closely succeeding circuit interruptingoperation will be delayed due to the dashpot action of core 62 indashpot sleeve 70 located within solenoid coil 12.

Of course, if the excess current condition through solenoid coil 12causing a circuit opening operation of the breaker does not persist,counting piston 80 will slowly reset as previously described, so that ifa permanent condition comes on the circuit at a later time, the normalbreaker will again go through the same sequence of one or two fastcircuit opening operations followed by time delay operations to lock-outthe breaker after the predetermined number of closely successiveoperations has occurred to cause extension 86 of the counting piston toengage and move operating extension 58 of toggle lever 38 upwardly.

The structure thus far described is substantially the same as thatdisclosed in detail in the copending application Serial No. 787,206 ofJames M. Wallace et al., entitled Automatic Reclosing Circuit Breakers,which was filed November 20, 1947, and assigned to the assignee of thepresent invention. However, in order to provide an automatic reclosingcircuit breaker which can be applied to a distribution line betweenreclosing circuit breakers of the customary type which have adjacentratings, and so double the length of the line which is protected, theconstruction of the circuit breaker of the Wallace et a1. patent hasbeen modified in several respects.

For the purpose of obtaining the proper coordination of circuit breakerswhen it is desired to use an additional breaker, intermediate breakersof the usual or normal type, which are of adjacent ratings, it isdesirable that the breaker to be thus utilized have greater than theusual time delay. This may be accomplished in any one of several ways,such as, for example, by reducing the radial clearance between the core62 and the dashpot sleeve 70 from the usual 3 mils or so, to about 1mil. Other ways would be by using a more viscous fluid in the dashpot,or by designing the dashpot with a greater diameter, so as to requirethe movement of a greater volume of fluid. Yet another way would be touse a brake of the type such as is disclosed in the copendingapplication Serial No. 113,933 of Andrew W. Edwards, entitled AutomaticReclosing Circuit Breakers, which was filed on September 3, 1949, andassigned to the assignee of the present invention. The delayed time maybe compared with that of a normal circuit breaker by comparing the curveBr of Fig. 3 of a modified 25 ampere reclosing circuit breaker with thecurves Cl and Ct, which are, respectively, the instanta- 6 neous anddelayed curves for a normal 25 ampere reclosing circuit breaker. Thecurves A1 and At represent the instantaneous and delayed curves of thenormal 50 ampere reclosing circuit breaker, respectively.

In order to selectively delay the initial opening of the circuit breakerwhen the circuit voltage is either substantially normal, or has beenreduced therefrom by reason of the circuit impedance, by reason of acurrent flowing, which is less than several times the normal loadcurrent, being in the present instance, for example, less than about 200amperes, the counting piston may be provided with an enlarged section 81adjacent the upper end of a reduced section 79 for blocking the fluidpassage 76.

The piston 80 may be provided with a spring 83 which is disposed to biasthe piston upwardly to a position in which the enlarged section 81 isabove the passage 76, so as to provide for freely venting the dashpot.Electromagnetic means such as the U-shaped core 85 of magnetic metalhaving an operating winding 87 thereon, may be mounted on the casting 8by means of a support 88 for cooperating with an armature 89 mounted onthe extension 86 of the counting piston. The core 85 and armature 89 maybe so disposed that when the winding 87 is energized with a voltagecorresponding to the normal voltage of the circuit, or when the currenttherein is not more than several times the normal load current, thearmature 89 holds the piston 80 down against the bias of the spring 84so that the enlarged section 81 completely blocks the passage 76 andenables the dashpot 6270 to provide the maximum time delay for a circuitinterrupting operation. The winding 87 may be connected by leads 90 to asuitable source of control voltage.

Referring to Fig. 2, it will be seen that a reclosing circuit breaker Bembodying the features of our invention may be connected betweenreclosing circuit breakers A and C which may be of adjacent ratings, forexample, 50 amperes and 25 amperes, respectively. The breaker A may, forexample, be set for all time lag operation by having the passage 76plugged. The breaker A may be connected to a suitable source byconductor 92, and the breaker B may be connected between adjacentsections 93 and 93 of a conductor which connects the breakers A and C.The winding 87 of the electromagnetic means may be energized byconnecting the leads 90 to the secondary winding 95 of a transformer 97connected to the line conductor 93 on the side of the breaker B adjacentthe breaker C.

Since the breaker B normally has a time current characteristic curve asindicated by the curve Bt, which is changed so as to provide a 25 ampereinstantaneous trip rating as indicated by the curve Ci, only aftereither one interruption by the breaker at A, or one interruption at B,the breakers A and C will coordinate in a normal manner for persistentfaults beyond the breaker C, the breaker B being unaffected by currentsof this magnitude and duration because of its normal greater time delaycharacteristic Br. For persistent faults between the breakers A and B,the breaker A will open and operate in a normal manner. For a faultbetween the breakers B and C, the voltage at the breaker B during thetime fault current is flowing will be somewhat dependent on themagnitude of the fault current. For a high fault current, the faultimpedance is low and the voltage at B is correspondingly low.Conversely, for relatively low fault currents, the fault impedance ishigher, and the voltage at B will be correspondingly greater. Theelectromagnetic means 8587 and the spring 83 are so designed that withthe voltages available at the breaker B for a fault current of, forexample, less than 200 amperes, the electromagnetic means will hold thecounting piston 80 in a downward position so as to block the fluidpassage 76 and maintain the breaker characteristic on the delayed curveBr.

In the following examples, the value of 200 amperes mass;

in the case of an automatic reclosing circuit breaker having a ampererating has been selected as illustrative of one level of overload atwhich the voltage of the circuit will drop sufficiently, because of thecircuit impedance, to permit the electromagnetic means 85-87 to releasethe piston and permit the spring 83 to'move it to its instantaneousoperation position. It will be realized that this value of current mayvary widely within the concept of the invention, and by using this valuefor purposes of illustration, we do not intend to be limited thereby.

If the fault current flowing is greater than 100 amperes, but less than200 amperes, the piston 80 will be held down. Circuit breaker A willthen operate to interrupt the circuit, and during the one secondreclosing time of circuit breaker A, the voltage at breaker B will bereduced to zero. The pull of electromagnetic means on the piston St? isremoved, and in the one second the spring 83 advances the piston 80 to apoint where the enlarged section 81 is clear of the passage 76, and thebreaker B will have a 25 ampere instantaneous tripping characteristiccorresponding to the curve C1. As the piston 80 advances, the air gapbetween the armature 89 and the core 85 is increased and the magneticpull between them is correspondingly reduced. Accordingly, when thecircuit breaker A recloses, the breaker B is conditioned for aninstantaneous operation. The downward pull on the piston 80 from theelectromagnetic means as a result of the restoration of circuit voltageat the breaker B will be so reduced because of the increased air gap, asto cause substantially no downward motion of the piston during theinstantaneous tripping time of the breaker B. The breaker B will thentrip instantaneously, and will, if the fault persists, repeat theoperation and lock out after a predetermined number of instantaneousoperations. The circuit breaker A remains closed after the initialopening operation, and service between A and B is uninterrupted.

For fault currents above 200 amperes, the voltage at the breaker B willnot be sufiicient for the electromagnetic means 8587 to maintain thepiston 80 in its lowermost position. Since it takes approximately onesecond for the piston 80 to advance to the instantaneous position, thecircuit breaker A will interrupt the circuit while the circuit breaker Bstill has the delayed time characteristic corresponding to curve Br.Once the circuit breaker A has operated, however, the breaker B willtransfer to instantaneous operation, and if the fault continues, willoperate a predetermined number of times and lock out in the usualmanner.

In the case of a fault between B and C, resulting in a fault currentbelow that of the minimum value for which the breaker A trips, thevoltage at B will be sufficient to hold the counting piston 80 down andthe breaker B will operate with a time characteristic corresponding tocurve Bt. The breaker B will accordingly interrupt the circuit after atime period determined by its characteristic curve. The breaker Boperates and advances the piston 89 in the usual manner throughoperation of the counting mechanism and eventually places itself oninstantaneous trip. The piston 80 will not resettle appreciabiy duringthe reclosing time of the breaker. Accord ingly, when the breakerrecloses, it is set for mstantaneous operation, and if the faultperslsts, 1t W111 interrupt the circuit a predetermined number of t1mesand then ut in the usual manner. l ii thet case of a fault beyond thebreaker C, the breaker B readily coordinates therewith. For faultcurrents which require a time longer than one second for the breaker Cto clear, the voltage at the breaker B will be sufficiently high topermit the electromagnetic means to maintain the counting piston 80 inits lowermost position during the time that the fault current isflowing. For higher currents, the breaker C W111 open in less than onesecond, and the piston 80 of the breaker B will not have sufficient timeto reach its instantaneous setting before the circuit is interrupted bythe breaker C. Thus, for a fault beyond the breaker C, the breaker Bdoes not-leave the curve Br and the reclosing'circuit breaker C willcoordinate in a normal manner with the breaker A in sectionalizing thedistribution line beyond the breaker C.

When the breaker B is reset after looking out, the counting piston 89retrieves in the usual manner, as a result of leakage of the fluid pastthe piston, until it reaches an equalized position with the spring 83.If at this time the circuit voltage is normal, the winding 37 isenergized and the piston 8t wil be slowly drawn down against the bias ofthe spring 83 to the fully reset position, ready for another cycle ofoperation.

From the above'description and accompanying drawing, it will be apparentthat we have invented a new and novel means for increasing the number ofsectionalizing points available with the usual reclosing circuit breakerratings. By providing a reclosing circuit breaker having an adjustabletime characteristic which is responsive to the circuit voltage at thebreaker, we have provided a means for telling the breaker whether or notthe breaker ahead of it has tripped so that it can adjust its timingcharacteristics accordingly.

Since certain changes may be made in the above-described construction,and different embodiments of the invention may be made without departingfrom the spirit and scope thereof, it is intended that all the mattercontained in the above description and shown in the accompanying drawingshall be considered as illustrative and not in a limiting sense.

We claim as our invention:

1. An automatic reclosing circuit breaker comprising, separablecontacts, an operating mechanism for actuating said contacts,electroresponsive means operable in response to an overload on a circuitto effect operation of the operating mechanism to cause separation ofsaid contacts, means for effecting operation of said mechanism forautomatically closing said contacts following a circuit openingoperation, time delay means operable to delay operation of theelectrosponsive means and delay opening operations of said breaker,counting means having a movable part advanced by said electroresponsivemeans to render the time delay means operable after a predeterminednumber of opening operations, and electromagnetic means operable to movesaid part in the opposite direction to render the time delay meansoperable independently of the counting means.

2. An automatic reclosing circuit breaker comprising, separablecontacts, an operating mechanism for actuating said contacts,electroresponsive means operable in response to overload currents toeffect operation of the operating mechanism to effect separation of saidcontacts, time delay means operable to delay operation of said electroresponsive means, counting means having a movable part advanced byoperation of the electroresponsive means operable after a predeterminednumber of contact separating operations to render the time delay meanseffec tive, and means operated by a circuit voltage of substantiallynormal value to actuate the movable part of said counting means torender the time delay means effective initially.

3. An automatic reclosing circuit breaker comprising, separablecontacts, an operating mechanism for said contacts, electroresponsivemeans operable in response to an overload current to move a magneticcore a predetermined distance, means actuated by said core for actuatingthe operating mechanism for causing separation of said contacts, dashpotmeans operable to delay movement of said core, said dashpot means havinga vent, valve means operable in one direction in response to movement ofsaid core to close said vent and render the time delay means operable,means normally biasing the valve means to an intermediate inoperativeposition,

and electromagnetic means operable to actuate the valve means in theopposite direction to render the time delay means operable in responseto a predetermined circuit voltage.

4. An automatic reclosing circuit breaker comprising, separablecontacts, an operating mechanism for said contacts, electroresponsivemeans including a coil connected in series relation with said contactsand a magnetic core movable to effect operation of the mechanism to openthem in response to an overload current, means for automatically causingoperation of the mechanism to effect engagement of said contactsfollowing a circuit opening operation, dashpot time delay means actingon said core operable to delay separation of said contacts, valve meansoperable after a predetermined number of circuit opening operations toblock venting of the dashpot to render the time delay means operable,means biasing the valve means to an inoperative position, andelectromagnetic means energized in accordance with the voltage of thecircuit, said electromagnetic means being operable to effect operationof said valve means against said biasing means to initially blockventing of the dashpot so long as the circuit voltage is above apredetermined operating value.

5. An automatic reclosing circuit breaker comprising, separablecontacts, an operating mechanism for said contacts, electroresponsivemeans having a movable part operable in response to an overload on acircuit to actuate said mechanism and effect separation of saidcontacts, dashpot means operable to delay movement of said part andseparation of said contacts, valve means normally providing a vent forsaid dashpot means to render the dashpot means inoperative, countingmeans advanced by successive operations of said electroresponsive meansto effect operation of the valve means to close the vent, means normallybiasing the valve means to an inoperative position, and electromagneticmeans including an operating winding disposed to be energized inaccordance with the voltage of the circuit to effect operation of thevalve means against said biasing means to close the vent and render thedashpot means operable independently of the counting means 6. Anautomatic reclosing circuit breaker comprising, separable contacts, anoperating mechanism for said contacts, electroresponsive meansresponsive to overload currents to move a core for actuating themechanism to separate said contacts and effect a circuit interruptingoperation, dashpot means operable to delay movement of said core, valvemeans disposed to control a vent for said dashpot means, means biasingsaid valve means to an intermediate position to normally open said ventand render the dashpot means ineffective, counting means actuated byclosely successive operations of the electroresponsive means operableafter a predetermined number of contact separating movements of saidcore to actuate the valve means in one direction to close said vent, andelectromagnetic means including an operating Winding disposed to beenergized in accordance with the voltage of the circuit to oppose thebiasing means and actuate the valve means in the opposite direction toclose the vent so long as the voltage is above a value corresponding toa predetermined value of overload current for the circuit.

7. An automatic reclosing circuit breaker comprising, separablecontacts, an operating mechanism for said contacts, electroresponsivemeans having a movable part responsive to overload currents to effectoperation of said mechanism to effect separation of said contacts, timedelay means operable to delay movement of said part to effect separationof said contacts, a movable member selectively operableto render thetime delay means effective or ineffective, biasing means operable tomove said member to a position to render the time delay meansineffective, counting means operable to move said member to a differentposition in response to a predetermined number of operations of saidelectroresponsive means, and voltage responsive means operable to opposethe operation of the biasing means and move the member to yet anotherposition for rendering the time delay means effective.

8. An automatic reclosing circuit breaker comprising, separable contactmeans, an operating mechanism therefor, electroresponsive means having amember movable in response to a fault current to actuate said mechanismto effect separation of said contacts for interrupting a circuit, saidcontacts being biased to reclose following a separation, normallyineffective time delay means operable to delay movement of the membereffecting separation of said contact means, counting means having a partadvanced by closely successive operations of the electroresponsive meansoperable only after a predetermined number of contact separations torender the time delay means effective, biasing means normally operableto bias said part of the counting means to a position to render the timedelay means ineffective, and means including electromagnetic meansopposing the biasing means for moving said part to a different positionfor rendering the time delay means effective in response to apredetermined electrical condition of the circuit.

9. An automatic reclosing circuit breaker comprising, separablecontacts, an operating mechanism for said contacts, electroresponsivemeans having a member operable to effect movement of said mechanism toeffect separation of said contacts to interrupt a circuit in response toa fault current in the circuit, means biasing the mechanism forreclosing said contacts following a separation, time delay meansoperable to delay movement of said member to effect separation of thecontacts, counting means having a part advanceable in one direction torender the delay means operable and to lock the contacts separated aftera predetermined number of separations, biasing means biasing saidadvanceable part to an intermediate position for rendering the timedelay means ineffective, and voltage responsive means operable toactuate said advanceable part in the opposite direction to a differentposition to render the time delay means effective to delay separation ofthe contacts except when the circuit voltage falls below a predeterminedvalue.

10. An automatic reclosing circuit breaker comprising, separablecontacts, an operating mechanism for said contacts, electroresponsivemeans having a part movable in response to a fault current in a circuitto actuate the operating mechanism to effect separation of the contactsto perform a circuit interrupting operation, said contacts being biasedto effect a circuit closing operation upon interruption of the circuit,time delay means operable to delay movement of said part to effectseparation of said contacts, a member movable to different positions torender the time delay means effective and ineffective, respectively,biasing means operable to move said member to one position to normallyrender the time delay'means ineffective and provide for substantiallyinstantaneous separation of said contacts, voltage responsive meansoperable to oppose the biasing means and move the member to a differentposition for effecting delayed separation of the contacts, and timedelay means for delaying operations of the movable member under theinfluence of voltage responsive means.

11. An automatic reclosing circuit breaker comprising, separablecontacts, an operating mechanism therefor, electroresponsive meanshaving a movable part operable to actuate the operating mechanism toseparate the contacts in response to a fault current, time delay meansoperable to delay movement of said part to effect separation of thecontacts, counting means having a part advanced by a predeterminednumber of closely consecutive operations of the electroresponsive meansto effect operation of the time delay means and to effect a locking openof said contacts, and voltage responsive means 1 1 operable to retractsaid part and effect operation of the time delay means independently ofthe counting means to delay separation of 'said contacts so long as thevoltage of the circuit remains above a predetermined value.

References Cited in the file of this patent UNITED STATES PATENTS '12Albrecht June 22, Connell Mar. 3, Spurgeon Jan. 19, Wallace et al, June1, Kyle et al. Jan. 18, Matthews Nov. 1, Van Ryan et al. July 10, VanRyan et a1. July 17, Edwards Mar. 25, Wallace et a1. Jan. 20,

